Turbomachine systems are often used to process multiphase fluids, for example, in pipeline applications, which provide a unique set of challenges to system designers. In some low flow-rate applications, the multiphase fluid may be a relatively well-mixed flow of gas and liquid. As such, a generally expected combination of gas and liquid arrives at the turbomachine, which may be separated and efficiently handled by appropriate fluid handling equipment (e.g., a compressor and a pump). However, in some higher-flow rate systems, a periodic flow may develop, in which, at some points, a disproportionately large percentage of the flow is liquid (i.e., a slug), while at other points, a disproportionately large percentage is gas. In some cases, the slugs can grow to occupy an entire cross-section of the pipeline, such that the denser liquid slugs separate pockets of gas. In severe cases, the slugs are preceded by no flow and followed by high-pressure gas flow. Further, the occurrence and position of the slugs can be relatively difficult to predict.
These slugs present a challenge, as it may be difficult to completely separate them from the gas without depriving the compressor of process fluid or flooding the separator. Accordingly, slug damping techniques and systems are often employed upstream of such processing equipment to reduce slug formation and propagation. Despite precautions taken to avoid the propagation of slugs, however, slugs often still reach the turbomachine systems.
To handle the slugs, the turbomachine systems generally include one or more slug catchers. Various types of slug catchers are known, but the general principle is that the slug catchers provide a buffer volume sufficient to store the largest slugs expected to be received from the pipeline. Accordingly, such slug catchers are typically large and heavy, substantially adding to the footprint of the system. In some applications, however, especially for offshore or subsea hydrocarbon production, space is at a premium, thus it is desirable to reduce the system footprint wherever possible. Each component is, therefore, carefully designed to occupy the least amount of space possible, while still providing for maximum operating efficiency. Slug catchers, however, remain bulky and heavy, as they must provide sufficient volume and handle sufficient pressures to accomplish their function.
What is needed is a system and method for effectively handling slug flow, while providing a reduced footprint for the turbomachine system.